Flat colorectal neoplasms: definition, importance, and visualization on CT colonography

Area of Science:

• Gastroenterology
• Radiology
• Oncology

Background:

• Flat colorectal neoplasms are challenging to detect with standard colonoscopy.
• Early detection of these lesions is critical for preventing colorectal cancer progression.

Purpose of the Study:

• To define flat colorectal neoplasms.
• To review CT colonography (CTC) findings for these lesions.
• To discuss techniques and pitfalls in CTC detection.

Main Methods:

• Review of existing literature on flat colorectal neoplasms and CTC.
• Analysis of characteristic CT colonography findings.
• Discussion of visualization techniques and diagnostic challenges.

Main Results:

• Flat lesions on CTC appear as plaque-shaped mucosal elevations, sometimes with central depression.
• Thickened haustral folds and nodular mucosal surfaces can indicate flat lesions.
• Optimal CTC sensitivity and techniques for flat lesions are not yet established.

Conclusions:

• CTC can visualize flat lesions as mucosal elevations; however, sensitivity is not fully determined.
• Advanced techniques like 3D endoluminal fly-through, fecal tagging, IV contrast, and specific window settings may improve detection.
• Further research is needed to establish optimal CTC protocols for identifying flat colorectal neoplasms.